Fuse-type circuit breaker

ABSTRACT

Fuse-type circuit breaker of small dimensions and of increased safety applicable especially to household uses, provided with a pair of blades and a pair of blade supports and a fuse connecting each individual blade to its corresponding blade support. One of the pair of fuses being responsive to current and the other being responsive to ambient temperature.

United States Patent [191 Sato [ Jan. 15, 1974 FUSE-TYPE CIRCUIT BREAKER [76] lnventorz Katsuyasu Sato, 6, Mitsuya Kitadori 3-chome, l-ligashiyodogawa-ku,

Osaka-shi, Japan [22] Filed:- May 27, 1971 [21] App1.No.: 147,451

[52] U.S. Cl 337/269, 337/198, 337/401,

337/412 [51] Int. Cl. H0lh 85/16 [58] Field of Search 337/197, 198, 268, 337/269, 401, 412, 414, 416, 261, 262, 263, 269, 283

[56] References Cited UNITED STATES PATENTS 1,850,672 3/1932 Heller 337/269 1,886,706 11/1932 MacDonald 337/269 3,535,667 10/1970 Harnish et a1. 337/269 X McLaren 337/269 X 434,168 8/1390 Wurts 337/283 2,640,126 5/1953 Eggers 337/269 1,056,951 3/1913 Sherer 337/416 261,265 7/1882 Seymour... 337/412 1,959,211 5/1934 McNamara.. 337/269 1,973,396 9/1934 Sowka 337/269 Primary ExaminerBernard A. Gilheany Assistant Examiner-F. E. Bell Att0rneyClairo Ceccon 5 7 ABSTRACT Fuse-type circuit breaker of small dimensions and of increased safety applicable especially to household uses, provided with a pair of blades and a pair of blade supports and a fuse connecting each individual blade to its corresponding blade support. One of the pair of fuses being responsive to current and the other being responsive to ambient temperature.

5 Claims, 2 Drawing Figures FUSE-TYPE CIRCUIT BREAKER BACKGROUND OF THE INVENTION This present invention relates to a fuse-type circuit breaker, especially to a fuse-type circuit breaker for domestic use, for example, in connection with household electrical appliances by coupling the appliance electric cord to the electric power outlet.

In electric wiring systems the electric power cable connecting the main circuit breakers at the point of electric entry to a building with the wall outlets distributed within the building is generally made to carry sufficient electric capacity, and no serious safety problem exists. However, the wiring between the wall outlets and the individual electric appliances is of various kinds and specifications and frequently vinyl resin insulated cables are used which have a low safety factor. If high current is passed through a cable of this type in a concentrated manner resulting, for example, from a sudden surge of current, a dangerous condition occurs.

The present invention has the objective of preventing the aforesaid hazards by controlling the current flowing from a wall outlet to an electric appliance.

Recently, a number of electric appliances have been developed, such as electric razors or flash lights, which are powered by charged accumulators contained in them. These accumulators arecharged by means of inserting the charging plug provided with the appliance directly into the wall outlet. If overheating of some defective portion of the electric appliance occurs as a result of a surge of current and a fire begins, the tire would immediately spread to the wall on which the outlet is fixed.

The present inventionis meant to offer a means of fire prevention by cutting off the electrical current if a high temperature is produced by a fire in the electric appliance.

The fuse-type circuit breaker for the above mentioned purposes is inserted into the wall outlet and the space required for it is a minimum.

Another objective of this invention is to offer a compactly dimensioned fuse-type circuit breaker, the thickness of which is reduced to a minimum by arranging a pair of blades as well as -a pair of blade supports in opposing positions wherein the straight lines connecting each individual pair will intersect each other.

It is conventional practice to install a fuse-type circuit breaker where the electric cable is first introduced inside a house. Also, in case a plurality of electric appliances are employed, each individual electric appliance is generally equipped with a fuse. Additionally, in specific conditions, the wall outlet may also be equipped with a fuse inside.

However, the fuse type circuit breaker installed at the electrical entry to the house has as its function the controlling of overall current flowing to the house. Accordingly, if a high electric current happens to flow in a single line located downstream of the main cable and the particular current remains within the controlling limit of the main circuit breaker, no preventive change can be expected and no action is taken for eliminating a possible fire hazard.

Furthermore, even though special emphasis is placed on the safe performance of modern electrical appliances, not all of these electrical appliances contain internal fuses. In addition, some private houses still have obsolete and hazardous electrical appliances in use.

When a wall outlet contains within it a fuse, then only electric current of a limited intensity is allowed to flow to the wall outlet and the intensity of the current so limited can not easily be changed nor can the fuse be easily removed.

SUMMARY OF THE INVENTION By applying this inventionfa fuse-type circuit breaker of an extremely simple construction is available, for preventing electrical accidents in electrical appliances and electrical equipment and at the same time, to improve the safety performance of these equipments. The circuit breaker has a pair of blades and a pair of blade supports so arranged that their respective lines intersect. The overall dimensions will not extend beyond a standard plug and thus a compactly built circuit breaker occupying very limited space can be obtained. When the fuse-type circuit breaker constructed in accordance with the present invention is employed for household use and is inserted into the wall outlet, it does not stick out of the wall on which the socket is installed and further, the fuse of the circuit breaker is placed in the space between the blade and blade support whose connecting lines intersect through an angle of thereby not requiring any surplus space. By means of the above mentioned fundamental constructional concepts, a distinctive feature of having an extremely limited space requirement can be achieved.

The present invention provides a fuse-type circuit breaker of simple construction and compact dimension available for use with household electrical appliances by coupling the appliance cord to an electric wall outlet. The aforesaid circuit breaker adds a high standard of safety by preventing any overload, short circuit or other electrical hazardous accidents occurring in electric appliances and electrical equipment caused by defective contacts and other perilous failures.

DESCRIPTION OF DRAWINGS FIG. 1 shows an elevation sectional view of a fusetype circuit breaker embodying the present invention;

FIG. 2 shows a plan view of the internal structure with a removed cover.

DESCRIPTION OF PREFERRED EMBODIMENT A detailed description of a practical example embodying the present invention shall be presented in conjunction with the attached drawings. A main body 1 of a fuse-type circuit breaker is constructed of electrical insulating non-flammable or hard to-ignite material, such as synthetic resin. On the top surface of the main body, two pairs of recesses 2, 2. and 3, 3 are provided. Recesses 3, 3' have holes 3a, 3a extending to the bottom. The recesses are arranged in a symmetric position with respect to the center such that the lines joining the opposedly positioned recesses 2, 2 and 3, 3, respectively are made to intersect each other at the center. The recesses 2 and 3 and also 2' and 3' are each connected through grooves 4, 4'.

In each recess 2 and 2', metallic blades 5 are installed such that the top portion of the blade sticks out of the top surface of the main body. In each individual recess 3 and 3, the blade supports 6 and 6' made of bent metallic material are installed with their respective clips 6a, 6a driven through the holes 3a, 3a and from the bottom. A pair of blades fixed on the plug of an electric cord is allowed to be set into the aforesaid holes 3a, 3a through the blade supports 6, 6'.

The blades 5 and blade supports 6, 6' are joined within the grooves 4 and 4', by a current fuse 7a and a temperature fuse 7b which can melt at an electric current higher than the rated current or by an increase in the temperature.

The fuses 7a and 7b, together with the blades 5 and blade supports 6 6, are fixed to the main body by means of bolts.

A cover 8 mounted on the body 1 and the main body, may be of a circular of a rectangular shape.

ln a fuse-type circuit breaker of the above described construction embodying the present invention, when an emergency situation occurs, for example, by overloading, short circuitingor by other irregular electric phenomena which cause the flow of an excessive high electric current, the circuit becomes open because of the melting of the current fuse 7a. When the fuse-type circuit breaker is abnormally heated caused by an improper contact resulting in an increase of contact resistance or by any other reason when a predetermined temperature is reached, the temperature fuse 7b melts away to break the circuit. Accordingly, a possible accident in the electric equipment can be eliminated.

I claim:

1. A fuse-type circuit breaker comprising a main body, a pair of blades projecting from one side of said body, a pair of blade supports contained within said body and extending almost entirely through said main body, two pairs of opposed fixing points located on said one side of said body, said blades connected to the body at one pair of opposed fixing points, and said blade supports connected to the body at the other pair of opposed fixing points, two grooves contained in the surface of said one side of said body, each groove containing a fixing point from each pair of said opposed fixing points, a current fuse located in one of said grooves, and a temperature fuse located in the other of said grooves, each of said fuses interconnecting the fixing points contained within their respective grooves, and wherein a line connecting said blades and a line connecting said blade supports intersect within said body.

2. A fuse-type circuit breaker, as in claim 1 and wherein said lines intersect at the center of said body.

3. A fuse-type circuit breaker, as in claim 1, wherein said blade supports are capable of receiving a further pair of blades from another side of said main body.

4. A fuse-type circuit breaker, as in claim 1, wherein said main body is constructed from a material having electrical insulating and non-flammable properties.

5. A fuse-type circuit breaker, as in claim 1, wherein said body is of a circular shape. 

1. A fuse-type circuit breaker comprising a main body, a pair of blades projecting from one side of said body, a pair of blade supports contained within said body and extending almost entirely through said main body, two pairs of opposed fixing points located on said one side of said body, said blades connected to the body at one pair of opposed fixing points, and said blade supports connected to the body at the other pair of opposed fixing points, two grooves contained in the surface of said one side of said body, each groove containing a fixing point from each pair of said opposed fixing points, a current fuse located in one of said grooves, and a temperature fuse located in the other of said grooves, each of said fuses interconnecting the fixing points contained within their respective grooves, and wherein a line connecting said blades and a line connecting said blade supports intersect within said body.
 2. A fuse-type circuit breaker, as in claim 1 and wherein said lines intersect at the center of said body.
 3. A fuse-type circuit breaker, as in claim 1, wherein said blade supports are capable of receiving a further pair of blades from another side of said main body.
 4. A fuse-type circuit breaker, as in claim 1, wherein said main body is constructed from a material having electrical insulating and non-flammable properties.
 5. A fuse-type circuit breaker, as in claim 1, wherein said body is of a circular shape. 